Synthesis and montmorillonite-intercalated behavior of dendritic surfactants

Abstract

A series of novel dendrons serving as surfactants for surface modification of montmorillonite (MMT) have been synthesised via a convergent approach. The most distinguishing characteristic of the prepared dendrons is the long alkyl chain at the periphery. This would certainly bring about good solubility, high yield and easy purification. By simple acidification of the “head group” upon the dendron and then ion-exchange with Na⁺-MMT, the interlayer distance could be enlarged significantly between the layered silicates. The organic/inorganic ratio determined by thermogravimetric analysis (TGA) is in the range of 60%–91%. This also confirms the occurrence of dendron ion-exchange with Na⁺-MMT. Transmission electronic microscopy (TEM) reveals the intercalated and exfoliated morphology of the dendron-modified MMTs. Modification using the generation 2 dendritic surfactant (G2) with molecular weight (M_w) = 2887.5 has achieved the exfoliated morphology in this work.